Continuous sample collecting device



Nov. 21, 1950 F. T. HALL CONTINUOUS SAMPLE COLLECTING DEVICE:

Filed May l2, 1945 of, 'nda ou con VINVEN-l-OR FREDERlCK T HALL 8%ATTORNE Patented Nov. 2l, 1950 CONTINUOUS SAMPLE COLLECTING DEVICEFrederick T. Hall, Bartlesville, Okla., assignor to Phillips PetroleumCompany, a corporation o! Delaware Application May 12, 1945, serial No.593,466 4 claims. (ci. 'z3-421.53

This invention relates to an apparatus for sampling gases. In one of itsmore specic aspects it relates to an apparatus for composite, weightedand representative sampling of gases. and to a method of taking thesame.

Many devices have been used in sampling solid materials, for examplemechanical samplers which cut out a definite proportion of material intransit. Most of such devices obtain a composite but not a weighted orrepresentative sample since operation is based on the time rather thanon a rate of ow factor. Devices for the sampling of liquids arecomparatively simple provided the sampled liquids are nonvolatile. Thesampling of gases and/or of liquids which are gasesat atmosphericconditions is a more diiiicult problem. It is to this latter problemthat my invention is directed.'

An object of my invention is to provide an apparatus for use in thesampling of gases, and to provide a method of sampling gases.

Another object of my invention is to provide an apparatusfor use intaking composite, weighted, representative samples of gases,

Still another object of my invention is to provide an apparatus for usein taking composite, weighted, representative samples of gases r gasescarrying liquid in mist form, or liquids easily gasied under atmosphericconditions.

Still other objects and advantages of my apparatu-s will be apparentfrom a careful study of the following disclosure, in which Figure 1 is adiagrammatic sectional elevation of my iluid sampling apparatus taken onthe line I-I of Figure 2.

Figure 2 is a diagrammatic end elevation 0f my apparatus.

Referring to the drawing and specifically to Figure l numeral II refersto a tank or other vessel in which a. liquid I2 is held for excludingair or foreign gas from the gas sample. A sampling wheel I3 is fullyimmersed in this liquid and the wheel is so disposed as to rotate in avertical plate` The wheel I3 is rigidly supported on a shaft I4 whichextends through a side wall of the vessel for motive power purposes. Apacking gland I5 prevents leakage of liquid while permitting shaft I4 torotate freely. The sampling or bucket wheel I3 is composed of twocircular plates held together by a circular band of metal I6 giving thewheel the appearance of a spool or reel of relatively short lengthcompared to the diameter. Bucket plates I1 are welded or otherwiserigidly attached to the circular metal band I6 and to the two circularplates to make a type of gastight bucket Il under which gas in processof sampling is caught and transferred from the stream of rising gasbubbles coming from a nozzle I9 to a position directly under an invertedfunnel 20. With all the bucket plates I1 being of the same size andwelded in place at the same angle with respect to the radius of thebucket wheel all buckets have substantially the same volumes.

A tube 2I conducts the gas sample from a main gas line 23 t0 theupwardly directed nozzle I9.

'This sample line contains a manually operated valve 22 for adjusting orcontrolling the amount of gas to be withdrawn from the main gas line 23.This valve may well be of a needle type valve since such valves can berather finely adjusted even manually.

A gas sampling bottle 24 or other container of suicient size is lledwith liquid and inverted as shown in the drawing. The funnel and bottleare supported by any means suitable, said means is not shown on thedrawing for purposes of lsimplicity The wheel shaft Il, as mentionedhereinbefore extends through the sidewall of the vessel II and isattached at its outer extremity to a source of power, such as a variablespeed electric motor 25 either directly or through a speed reductionmechanism 26.

It is intended that the speed of rotation of the bucket wheel shall beproportional to the rate of fluid flow in the main transfer line 23. Inother words if it is desired to take a composite, weighted,representative sample over a period of time, such an arrangement ofcontrols is necessary. To do this I usey a rate of flow controllermechanism 28. This rate of ow controller mechanism 28 is composed ofseveral parts, including two pipe ilanges 21 having a, standard oriceplate 29 inserted therebetween. The flanges are drilled to take a smallpipe, such as 1A, inch pipe, which pipes or tubes 30 lead to thecontroller instrument 3|. Pipe 32 brings instrument air of very constantpressure from a source, not shown, to the instrument, while pipe 33conducts "control air from the instrument to a diaphragm motor mechanism34. The diaphragm 35 of this latter mechanism is made of rubber or othergas-tight, flexible, sheet material. To the center of this diaphragm isattached a push rod 36 the other end of which in turn is attached tomember 31 which is pivoted at 31A. The movable end of this pivotedmember is attached to a variable resistance mechanism 38 which uponmovement of the dlaphragm 25 operates to vary or to control voltage froma source of power so that the speed of electric motor 25 may be variedaccordingly. The rate ofv dow controller, motor diaphragm and variableresistance apparatus are standard equipment and may be purchased assuch.

For carrying out a. hydrocarbon sampling operation according to myinvention, I construct and assemble the apparatus as hereinabovedescribed. The tank il is now illled with a brine or salt water solutionsince hydrocarbon gases are not at all or only very slightly absorbed bysuch a solution. Similarly the sample bottle 2l is filled with such abrine solution and inverted over the funnel 2li as indicated in thedrawing. With the tank and bottle illled with brine, and withhydrocarbon gas or mixture of such gases. for example, passing throughthe main line 23, the needle valve 22 is opened to such an extent thatgas issues from the sample tube nozzle is and bubbles upward through thebrine as indicated in Figure 1 of the drawing. A switch 39 in the powerline to the electric motor 25 is closed and the operation of themechanism is thus begun. When the needle valve 22 is opened the properextent suillcient gas issues from nozzle i9 to till each f bucket" as itpasses downward and countercurrently to the upward iiowing gas bubblesand an excess of bubbles overilows each bucket and rises to the top ofthe brine to be lost to the air or disposed of as desired. Each bucketthen passes on around its circular path and at about the bottom of itspath of travel the gaseous content thereof begins to flow upward asshown in Figure l, the bubbles being caught under the funnel 20 anddiverted into the gas sampling bottle 2l.

In case the flow of hydrocarbon gas or gases through the main gas lineis constant, then the pressure differential across the oriilce member 29remains constant and the speed of the electric motor and of the bucketwheel accordingly remains constant. I1' the gas sample bottle is a 5gallon bottle then the capacity of the wheel buckets may be relativelysmall and such that in normal operation the bottle may be nearly illledwith sample during a 12 or 24 hour period if samples over such periodsare desired.

i When increased gas ilow occurs in main line 23, then the pressuredifferential across the orifice 29 increases and'controller 3i operatesto increase the air pressure in the control air line 33 and accordinglythe air pressure on the diaphragm increases. the push-pull rod 38 dropsto lower member 3T to cut out a portion of the variable resistance whichoperation permits increased voltage to the electric motor and its speedand accordingly the sample bucket wheel speed is increased. Thus, thespeed of sample taking is increased when the gas flow in pipe 23increases.

- Likewise, when gas ilow in pipe 23 decreases the pressure differentialacross the orifice decreases and the controller 2| operates to decreasethe control air pressure on top of the diaphragm and a spring 40 thenraises the diaphragm. The rheostat then operates to decrease the voltageto the electric motor 25 and the sped of the latter and the bucket wheeldecreases and a slower rate oi' aas sample collecting results. l

There must always be an excess of gas issuing from the nozzle i9 overthat transferred by the buckets into the sample bottle so that i! thesample wheel speed is increased the sample buckets will still becompletely illled with sample 8&8.

4 My general method o! sampling may be applied to the sampling o!hydrocarbon liquids when the latter are easily vaporlzed at atmospherictemperature and pressure. In this case, the ori- -ilce plate 29 must beone adapted to measuring the ilow ot liquids, and such are commerciallyavailable. The needle valve 22 will then be opened very slightly or Justenough to permit sui.'- ilcient ilow of liquid therethrough. Uponpassage through this needle valve thc liquid hydrocarbon easilyvaporizes in the sample tube 2| so that only gas issues from the nozzleIl and from the nozzle I! the sampling operation is similar to thatdescribed in relation to gas sampling. When the liquid pressuredifferential across the oriilce 29 increases or decreases, the rate ofnow apparatus 3| operates to increase or decrease the control airpressure and the R. P. M. of the bucket wheel increases or decreases.

In this latter case. that is, the sampling of liquids, all compounds inthe stream should be vaporlzed on passage through the needle valve 22 astheir pressure is reduced to atmospheric.

My apparatus may be so operated as to give a 5 gallon or a l0 gallonbottle oi sample in substantially any time desired, as for example, over6 hour periods, 12 or 24 hours, or even shorter or longer times.Likewise smaller or larger bottles or bottles oi' any size may be used.

In case other gases than hydrocarbons are to be sampled some otherliquid than a salt water brine may need be used. The principle points tobe considered are the gas must not be dissolved nor a component gas oi amixture must not be selectively dissolved by the liquid orrepresentative samples cannot be taken. and the liquid should bereasonably inexpensive.

My apparatus is ilexible in construction land its use or operation maybe varied to meet many conditions. I have found it to be especiallysatisfactory for the sampling o! gas streams in oil rcilneries,lgasoline plants, and in synthetic hydrocarbon plants. Even though thegas composition changes concurrently with increased i'iow, the sampletaken is a true weighted, representative sample of the entire amount ofsus passed during the sampling period.

The materials of construction need not be special excepting possiblythat which is submerged in brine. This should of course be resistant tothe corrosive action of brine, The bucket plates i1 should possibly bewelded to the wheel portion so that the buckets will be gas tight.

The controller and electrical portions of my apparatus are standardvequipment and descriptions may be found in equipment catalogues, butthe combination of parts to provide a gas sampler constitutes one aspectof my invention. Numerous changes and substitution of old elements maybe made without depart'ng from my invention which is deilned by thefollowing claims.

Having described my invention, I claim:

l. A continuous composite representative gas sample collecting devicefor collecting a. sample of gas from a gas line in which the rate offlow varies during the time of collecting said sample and from whichline substantially equal volumes of the sample are to be taken fromsubstantially equal divisional volumes of the total gas flowing in saidgas line during the taking of the sample, comprising in combination atank; a liquid which is substantially non-absorbent to said gas withinsaid tank: means for collecting given volumes of gas samples which meanscomprises a wheel having a plurality of substantially equal sizedpockets substantially equally spaced about its periphery, said wheelbeing submerged in said liquid; means for rotating said wheel in saidliquid at a speed substantially directly in proportion to the rate offlow in said gas line and adapted to be rotated, said pockets being sopositioned on said wheel that they will collect a rising gas on theirdownward motion through said liquid as the wheel. is rotated in itsnormal direction of rotation; a conduit adapted to constantly convey aportion of gas extending from said gas line to a point under said gassample collecting means, said conduit having an orifice under saidcollecting means; and a gas sample collecting container communicatingwith said tank below the surface of the liquid and positioned above saidwheel to collect and retain the measured volumes of gas samples as theyescape from said gas collecting wheel.

2. A continuous composite representative volatile fluid samplecollecting device comprising in combination a tank; a liquid which issubstantially non-absorbent to said volatile fluid, within said-tank; afluid conduit extending from said fluid containing line into said liquidand adapted to carry fluid at a rate substantially proportionate to therate of ow inl said line; a fluid sample collecting containercommunicating with said tank below the surface of said liquid; fluidsampling means having a pocket disposed in said liquid above an outletin said conduit to collect uniform amounts of iluid by displacement ofthe liquid by the iluid entering said pocket and to direct the escape ofall excess quantities of fluid away from said collecting container; andactuating means to move said pocket successively into fluid collectingposition and then into a position where said fluid will now into saidcontainer operatively connected to said iluid sampling means, saidactuating means moving said pocket at a rate substantially directlyproportionate to the rate of flow in said gas line.

3. A continuous composite representative volatile fluid samplecollecting device of claim 2 in which the fluid sampling means has aplurality of pockets disposed therein.

4. A continuous composite representative gas sample collecting devicefor collecting a sample of gas from a gas line in which the rate of flowvaries during the time of collecting said sample and from which linesubstantially equal volumes of the sample are to be taken fromsubstantially equal divisional volumes of the total gas flowing in saidgas line during the taking of the sample, comprising in combination atank capable of retaining a liquid therein; a conduit for constantlyconveying a portion of gas extending from said gas line to a pointwithin the lower portionof said tank; gas sampling means having a pockettherein, said means being positioned above said conduit; a gas samplecollecting container positioned above said gas sampling means; andactuating means for moving said pocket successively into gas collectingposition and then into a position where gas released from said pocketrises directly into said gas sample collecting container operativelyconnected to said gas sampling means, said actuating means adapted so asto move said pocket at a rate substantially directly propor tionate tothe rate of flow in said gas line.

FREDERICK T. HALL.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,364,035 Carter Dec. 28, 19202,245,679 Kelley June 17, 1941 2,356,845 Hines Aug. 29, 1944 2,380,977Lewis Aug. 7, 1945 FOREIGN PATENTS Number Country Date 468 Great Britainof 1911 Certificate of Correction Patent No. 2,530,463 November 21, 1950FREDERICK T. HALL It is hereby oerted that error appears in the printedspeccaton of the above numbered patent requiring correction as follows:

Column l, line 44, for the Word plate read plane;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the ease in the Patent Olce.

Signed and sealed this 30th day of January, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,530,463 November 21, 1950FREDERICK T. HALL It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows:

Column l, line 44, for the word late read plane;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the oase in the PatentOffice.

Signed and sealed this 30th day of January, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Oommzsszoner of Patents.

